Aaron Cassill

Professor, Biology
College of Sciences

Aaron Cassill always wanted to be a teacher.

Auspiciously influenced by great teachers since his elementary school years, Cassill has crafted his own unique pedagogy by emulating their examples of kindness, enthusiasm for sharing knowledge, and genuine interest in the maturation of one’s students. He sees his students as individuals and believes that his responsibility as a teacher goes beyond providing them with information, but also in assisting them in becoming the people they wish to be.

In class, Cassill often illustrates biology’s relevance to everyday life. He strives to show his students that there is no such thing as a fact, and that the pursuit of knowledge is an infinite progression, which they are all capable of contributing to.

“To me, teaching is about always moving forward and watching the limits of knowledge move out even further beyond us,” he said. “But this is not discouraging; instead it is the best part of the adventure.”

In his 18-year career at UTSA, Cassill has been a critical agent in the growth of the College of Sciences. He currently teaches Contemporary Biology, Genetics, and an Honors Colloquium (which he teaches with his wife, psychology professor Mary McNaughton-Cassill) called “Science and Psychology of Everyday Life”—all of which rapidly fill to capacity every semester.

When he teaches biology, Cassill said, “I want the students to always be aware of how amazing life is and how many complex layers go into even the most basic understanding of the material.”

A sentiment shared among his students is that Cassill’s courses are some of the most engaging and enjoyable offered at UTSA. “He conveys information on complicated scientific topics with impressive clarity, encouraging curiosity through frequent references to real-world applications and cutting-edge research,” wrote one former student.

Cassill is also active in promoting interest in science and mathematics from all age levels in San Antonio’s public school system. He is the director of STEM Initiatives for the College of Science and the associate director of the Minority Access to Research Careers (MARC) and the Minority Biomedical Research Scientists (MBRS) programs.

“By strengthening pre-college education, he increases options and opportunities for UTSA students well before they arrive at UTSA,” said geology professor Stuart Birnbaum. “His approach is much like gardening: sow the seeds, nurture the growing plant, and harvest the fruits of that labor.”